First Report of Candidemia Clonal Outbreak Caused by Emerging Fluconazole-Resistant Candida parapsilosis Isolates Harboring Y132F and/or Y132F+K143R in Turkey.

Clonal outbreaks of fluconazole-resistant (FLZR) isolates have been reported in several countries. Despite its being the second leading cause of candidemia, the azole resistance mechanisms and the clonal expansion of FLZR blood isolates have not been reported in Turkey. In this study, we consecutively collected blood isolates (= 225) from the fifth largest hospital in Turkey (2007 to 2019), assessed their azole susceptibility pattern using CLSI M27-A3/S4, and sequenced for all and , , and for a selected number of isolates. The typing resolution of two widely used techniques, amplified fragment length polymorphism typing (AFLP) and microsatellite typing (MST), and the biofilm production of FLZR isolates with and without Y132F were compared. Approximately 27% of isolates were FLZR (60/225), among which 90% (54/60) harbored known mutations in Erg11, including Y132F (24/60) and Y132F+K143R (19/60). Several mutations specific to FLZR isolates were found in , , and AFLP grouped isolates into two clusters, while MST revealed several clusters. The majority of Y132F/Y132F+K143R isolates grouped in clonal clusters, which significantly expanded throughout 2007 to 2019 in neonatal wards. isolates carrying Y132F were associated with significantly higher mortality and less biofilm production than other FLZR isolates. Collectively, we documented the first outbreak of FLZR blood isolates in Turkey. The , , and mutations exclusively found in FLZR isolates establishes a basis for future studies, which will potentially broaden our knowledge of FLZR mechanisms in MST should be a preferred method for clonal analysis of isolates in outbreak scenarios.